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io_uring: optimise commit_sqring() for common case

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It should be pretty rare to not submitting anything when there is
something in the ring. No need to keep heuristics for this case.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2019-12-30 21:24:46 +03:00 committed by Jens Axboe
parent ee7d46d9db
commit caf582c652
1 changed files with 6 additions and 8 deletions
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14
fs/io_uring.c
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@ -4501,14 +4501,12 @@ static void io_commit_sqring(struct io_ring_ctx *ctx)
{ {
struct io_rings *rings = ctx->rings; struct io_rings *rings = ctx->rings;
if (ctx->cached_sq_head != READ_ONCE(rings->sq.head)) { /*
/* * Ensure any loads from the SQEs are done at this point,
* Ensure any loads from the SQEs are done at this point, * since once we write the new head, the application could
* since once we write the new head, the application could * write new data to them.
* write new data to them. */
*/ smp_store_release(&rings->sq.head, ctx->cached_sq_head);
smp_store_release(&rings->sq.head, ctx->cached_sq_head);
}
} }
/* /*